In oil well pumping devices such as the balance beam type it is critical to maintain the integrity of the stuffing box and its packing about the reciprocating pump rod.
Many of these pumping devices are operated unattended in the field and failure of the stuffing box packing can cause loss of large volumes of oil and thus, large economic losses as well as environmental pollution.
Therefore, it is important to provide sensors at the well head for recognizing stuffing box failure and for generating a signal to alert responsible operators to take appropriate action.
A typical prior art device which signals a breakdown of the stuffing box is shown and described in U.S. Pat. No. 3,180,134. In the '134 patent stuffing box is surrounded by a reservoir of oil, produced by the well, maintained at a static fluid pressure which is substantially higher than the pressure at which the oil is produced from the well. A drop in oil pressure in the reservoir is a strong indication that the stuffing box is leaking. The differential in oil pressure is read and an appropriate sensor responds to the pressure drop and creates a signal notifying interested operators of the leaky stuffing box.
Another prior art sensing device is disclosed and described in U.S. Pat. No. 3,276,246 in which oil from a leaking main stuffing box is retained by an auxiliary stuffing box and thereafter directed to a reservoir. When the level of fluid in the reservoir reaches a certain level an appropriate alarm is sounded.